Fire extinguishing foam apparatus



July 25, 1939: F. L. BOYD 2,167,232,

\ FIRE EXTINGUISHING .FOAM APPARATUS Filed June 6,1936

M60 1 mellfifi" FISHER L. BQYD Patented July 25, 1939 PATENT OFFICE FIREEXTINGUISHING FOAM APPARATUS Fisher L. Boyd, Haverford,'Pa.', assignorto National Foam System, Inc., Philadelphia, Pa., a corporation ofDelaware Application June'6, 1936, Serial No. 83,887

1 Claim.

This invention relates generally to fire extinguishing systems and moreparticularly to improvements in apparatus for generating and deliveringfoam for the extinguishment of fires 5 which might occur in dip tanks,.drain boards, cleaning tanks and other such installations whereinvolatile, inflammable liquids are employed.

In the production of foam for fire extinguishing purposes the use ofreacting solutions of foam forming chemicals is well known in the art,the chemicals ordinarily employed being bicarbonate of soda and aluminumsulphate. When the separate solutions of these chemicals are combinedthere immediately results the production of a mass of bubbles of carbondioxide gas which is non-supporting of combustion and which may beapplied in the form of a smothering blanket to the fire to extinguishthe same. In order to increase the surface tension of the gas bubbles sothat the foam will have a more lasting and stable quality, a stabilizeris generally added to one or the other of the chemicals, this stabilizerbeing usually an extract of licorice root, oak bark or some, other suchmaterial known to .be usable for the purpose.

While the use of the above described foam has long been recognized inthe art as a dependable extinguishing agent in inflammable liquid fires,30.: its application to certain types of fires is frequently eifectedwith difiiculty and with considerable loss of valuable time.Particularly is this true in the case of those fire hazards, such as diptanks and the like. where the area involved is 351comparatively smalland the time element is of extreme importance, it being impracticable insuch instances to employ any type of apparatus except such as rendersthe foam automatically available toextinguish the fire.

40 .It is accordingly among the objects ofthe present invention toprovide anapparatus which operates automatically to generate and deliverfire extinguishing foam tothefire hazard area, the

apparatus being not only of exceedingly compact 45 design so as torequire a minimum of floorspace,

but also of a construction so simple that it may be operated andserviced by the ordinary inexperienced individual. 7 V

' A further object is to insure not only the auto- 50 matic generationof the foam within the foam tank but also the automatic discharge at auniform rate of all of the generated foam, and to that end the apparatusis devoid of moving parts interiorly of the foam tank which'requiretime.

55 =to operate, the two foam forming solutions, ac-

cording to, the present invention, being brought into reactingcombination by the use of a charge of compressed carbon dioxide gas orother gaseous pressure medium. Carbon dioxide gas is preferably employedbecause it is itself non-supporting of combustion and so combines withthe generated carbon-dioxide foam bubbles to increase the fireextinguishing capabilities of the foam blanket delivered from theapparatus.

Still another and important object of the in- 10 vention is to employ acompressed charge of carbon dioxide or other gas for instantly effectingthe necessary reacting combination between the normally separated basicand acid foam forming solutions, the arrangement being such that the '16foam generating apparatus may take the form of a stationary unit inwhich the only operating part is a plunger provided for piercing asealing disc to release the gaseous pressure medium from the cartridgeinwhich it is contained. 20'

Still other objects and advantages of the invention, such as thoserelating to details of con- 'struction' and economies effected therebywill be apparent hereinafter.

The invention consists in the combination, con- 25 ing' drawing, apreferred construction of the apparatus is shown, it being understood,of course, that this construction is only illustrative of the principlesof the invention and may be varied or modified as conditions warrantwithout. affecting or changing the operating principles of theapparatus.

In the said accompanying drawing: I

Figure 1 is a vertical sectional View of the apparatus constructed inaccordance with and embodying the principles of the present inven- 40tion;

Figure 2 is an enlarged sectional view of the upper part of theapparatus showing more particularly the arrangement for effecting therelease of the pressure medium from the cartridge within which it iscontained and the association of this cartridge with the foam generatingshank;

and I Figure 3 is a view showing the apparatus in elevation andconnected to a foam distribution system.

Referring now to the drawing and more particularly to Figure 1 thereofit will be observed that the apparatus of the present inventiongenerally comprises a main tank l0 having a removable top cover II.Preferably, the upper edge of the tank is provided with an out-turnedflange I2 upon which the cover I I rests and to which it is secured inany suitable manner, as by bolts or other securing devices not shown.Suspended within the upper part of the tank II] is an auxiliary vesselI3, the latter being more or less snugly fitted within the tank I and ofsuch depth as to provide a chamber or space It between the bottom wall Iof the suspended vessel I3 and the bottom wall ISA of the tank It whichis several times the capacity of the vessel I3. Preferably, the upperedge of the vessel I3 is also provided with an cut-turned flange I6which is adapted to overlie the flange I2 of the tank II] when thevessel I3 is suspended within the main tank, the flanges I2 and I6 andthe marginal edge of the tank cover II being so firmly secured togetheras to provide an hermetically sealed unit having separate compartments Il and I1.

Fixed to and forming part of the inner vessel I3 is a discharge tube 53,the longer branch I9 of which projects through the bottom wall I5 of thevessel I3 to a point adjacent the bottom of the main tank I9.Preferably, this branch I3 of the tube is welded or otherwise secured,as at 20, to the bottom wall I5 of the vessel I3. The shorter branch 2Iof the tube terminates immediately above the bottom wall E5 of thevessel I3, while the bight of the tube is located well in the upper partof the vessel I3. The tank is provided in the side wall thereof at apoint just below the bottom of the vessel I3 suspended therein with adischarge outlet 22 to which is adapted to be 7 connected a conduit 23forming part of the foam distributing system. Preferably, the dischargeoutlet is protected by a screen 2 5 to prevent the passage into the foamdistributing system of any foreign matter which might clog the conduitsand so impede the free passage therethrough of the foam. The largerchamber M, which is that provided in the tank It between the bottom I6thereof and the bottom wall of the suspended inner vessel I3 is adaptedto be filled with a solution of bicarbonate of soda, designated B, tothe level shown approximately in Figure l. The acid solution which isusually a solution of aluminum sulphate is received within the vessel II, the level of this latter solution being approximately that shown inFigure 1 which is below the upper curve of the tube I8. The acid andbasic solutions are thus normally maintained in separated relation andso long as this condition exists there is no generation of foam.Immediately, however, that the acid solution, designated A in Figure 1,is introduced into the basic solution B, a reaction occurs and foam isgenerated in the chamber I4, the pressure of this foam so generatedbeing sufficient to cause it to be discharged through the dischargeoutlet 22 and by way of the conduit 23 into the foam distributingsystem.

The introduction of the acid solution into the basic solution so as toresult in the generation of the desired foam is effected automaticallyand practically instantaneously by the means now to be described. Formedin the top cover I I of the foam tank is an interiorly threaded boss 24which is adapted to threadedly receive a removable closure cap 25, thelatter being provided with a centrally disposed exteriorly threaded boss26. The closure cap 25 and its depending boss 26 are axially bored, asat 21, and projected throughthis bore is a spring-biased plunger 28, thelower extremity 29 of which is fashioned into the shape of a punch. Anannular shoulder 39 formed on point M.

the plunger limits the upward movement of the latter through the bore 21and also serves as a seal for preventing the escape of the gaseouspressure medium or of the acid solution upwardly through said bore.

Threadedly secured to the depending boss 26 is an axially bored plug 3Ihaving an annular sealing disc seat 32 formed in its lower extremity.Secured in turn to this plug 3I, through the intervention of anintermediate body member 33, is a cartridge 34 adapted to contain acharge of compressed carbon dioxide gas or other such gaseous pressuremedium. The intermediate body member 33 is also provided with an annularsealing disc seat 35 which coacts with the seat 32 in the plug 3I toclamp therebetween a sealing disc 36 of copper or other such readilyruptureable material. The intermediate body member is further providedwith a restricted passage 31, while the plug 3| is provided in its upperportion with one or more radial apertures 38, from which it will appearthat when the sealing disc 36 is ruptured the gaseous mediumcontainedwithin the cartridge 34 is immediately discharged therefrom and passesupwardly through the restricted passage 37, the ruptured sealing disc 36and the radial passage or passages 38 into the interior of the vesselI3.

The gaseous pressure medium which is thus discharged into the chamber llof the suspended inner vessel I3 immediately forces the acid solu-. tionA through the tube I8 into the lower chamber I of the tank in which iscontained the basic foam-forming solution B. The acid and basicsolutions thus combine and react in the chamber I 3 to generate the fireextinguishing foam and as the latter is generated the pressure thereofis sufiicient to force the foam out of the chamber I4 by way of thedischarge outlet 22 into the conduit 23 and thence through the foamdistributing system, designated generally by the reference numeral 38 inFigure 3. Preferably, this foam dis tributing system comprises a seriesof branched conduits the terminal extremities of which are each equippedwith nozzles 39 for discharging the foam over the area to be protected.The exact form of the nozzle may vary depending upon the type of hazardwhich it is desired to protect against, it being preferable to employflared nozzles for dip tank protection, deflector nozzles for drainboard protection, and so on.

In order to effect the operation of the plunger 28 for piercing orrupturing the sealing disc 36 of the gaseous pressure medium cartridge,it is necessary only to strike it a sharp blow either manually or by amechanism of the type illustrated in the drawing and which includes aweight-operated lever M3 for depressing the plunger 28 in the event ofan occurrence of a fire within the protected zone. As shown in Figure 1,this lever 49 is connected by means of a cable 4| to a weight 42. thelatter being held in inoperative suspended. position by a second cable43 connected to a fixed The cable 43 includes in its length a fusiblelink 45 from which it will appear that in the event of a fire ofsufiicient intensity to melt the fusible link, the weight 12 will nolonger be restrained against dropping by the cable 43 and in so droppingwill cause the lever 40 to depress the plunger 28 in consequence ofwhich the sealing disc 36 will be pierced to release the gaseouspressure medium from the cartridge 34. The pressure medium so releasedfrom the cartridge is suificient to effect the transference of all ofthe acid foam-forming solution A into the chamber containing the basicfoam-forming solution with the result that foam is immediately generatedand delivered to the fire zone.

From the foregoing it will be apparent that the foam generating unit ofthe present invention is of exceedingly simple and compact design,requires little if any attention, is fully automatic and positive inoperation, includes no moving parts except the disc piercing plunger andis readily adapted for recharge by the simple expedient of removing thecover II to permit the replacement of the exhausted gaseous pressuremedium cartridge and the replenishing of the consumed acid and basicfoam-forming solutions. If desired, the tank Ill may be equipped with awash-out plug 46 for cleaning purposes.

It will be understood, of course, that the unit may be operatedautomatically by means other than illustrated in the drawing and thatthe construction of the unit may be varied without departing from theprinciples of the invention as defined in the appended claim.

What is claimed as new and useful is:

In an apparatus for generating fire extinguishing foam, in combination,a stationary vertical tank adapted to contain a foam-forming solution, aremovable vessel adapted to contain a second foam-forming solution, saidvessel being disposed within said tank in such manner as to maintain thetwo solutions normally in vertically separated relation, means affordinga normally sealed communicating passage between said solutions, saidmeans including a tube extending to a point adjacent the bottom of saidtank and having a reversely bent upper end communicating with theinterior of said vessel and a normally sealed charge of compressed gasdisposed interiorly of said vessel and adapted when opened to releasethe gas to thereby force the solution in said vessel under pressurethrough said communicating tube to the bottom of said tank for reactingcombination with the solution in the tank to form foam. 20

FISHER L. BOYD.

